Method of layer-by-layer application of treatment chemicals to fiber-based planar products and products made using same

ABSTRACT

The present invention relates to a method of applying treatment chemicals to a dry, creped tissue material, said method comprising the steps of:  
     a) applying a first treatment composition containing at least one treatment chemical to the dry, creped tissue material to produce a first layer having at least one first treatment chemical, and  
     b) applying at least one further treatment composition containing at least one other treatment chemical to produce at least one other layer on the first layer, said other layer having at least one other treatment chemical,  
     and a tissue material or tissue product obtainable according to this method.  
     The process of the invention enables the production of tissue products, wherein the treatment chemicals are optimally distributed, depending on their purpose of use, and can develop their properties.

SPECIFICATION

[0001] The present invention relates to a method of applying treatmentchemicals to fiber-based planar products, particularly tissue. It alsorelates to a device for performing the method and to the products madeusing same.

[0002] Within the framework of the present invention, the term “tissue”especially includes “tissue paper” or “raw tissue”, as is normallyproduced as a one-ply tissue web in the tissue (paper) machine, as wellas including multiply (intermediate) products, e.g. in the form ofmultiply doubled webs or in the form of master rolls for furtherprocessing and ready-made one-ply and multiply tissue products such aspaper handkerchiefs, facials, toilet paper, household towels such askitchen towels, hand towels and other wipes etc.

PRIOR ART

[0003] Based on the underlying correspondence of the productionprocesses (wet laying), “tissue” production is counted among the papermaking techniques. The production of tissue, or more accurately, rawtissue if the one-ply (intermediate) product manufactured on aspecial-purpose paper machine of the tissue or tissue paper machine ismeant, is delimited from paper production as a result of the extremelylow basis weight of normally less than 40 g/m² and as a result of themuch higher tensile energy absorption index as compared to paper. Thetensile energy absorption index is arrived at by relating the tensileenergy absorption to the test sample volume before inspection (length,width, thickness of sample between the clamps before tensile load).

[0004] Paper and tissue paper also differ in general with regard to themodulus of elasticity that characterizes the stress-strain properties ofthese planar products as a material parameter, depending on theproduction conditions, raw materials used and chemical additives.

[0005] A tissue paper's high tensile energy absorption index resultsfrom the outer and/or inner creping. The former is produced bycompression of the tissue paper web adhering to a dry cylinder as aresult of the action of a crepe doctor or in the latter instance as aresult of a difference in speed between two successive screens or e.g.between a sheet-forming screen and a so-called fabric or between twofabrics.

[0006] When applying the through air drying (TAD) technique for theproduction of raw tissue and the usual double-screen sheet formation inc-wrap configuration, for example, the so-called inner sheet-formingscreen can thus be operated at a speed that is up to 40% faster thanthat of the next fabric or that of the subsequent felt, the initiallyformed and already pre-drained paper web being transferred to the nextTAD fabric. This causes the still moist and as a result plasticallydeformable paper web to be internally broken up by compression andshearing, thereby rendering it more stretchable under load than a paperthat has undergone neither “internal” nor external creping.

[0007] This transfer of a still plastically deformable paper web at adifferential speed that simultaneously takes effect may also be broughtabout in other embodiments between a transfer fabric and the so-calledTAD imprinting fabric or between two transfer fabrics.

[0008] German has adopted the English-language term “fabric” todesignate paper machine covers that exhibit a screen-like fabricstructure in which synthetic threads are used as a thread materialinstead of metal wires.

[0009] Most of the functional properties typical of tissue and tissueproducts result from the high tensile energy absorption index (seeGerman standards DIN EN 12625-4 and DIN EN 12625-5). An example isrepresented by tissue products for hygienic applications (hygieneproducts, particularly hygiene paper products) which are e.g. used inpersonal grooming and hygiene, the household sector, industry, theinstitutional field in a very wide variety of cleaning processes. Theyare used to absorb fluids, for decorative purposes, for packaging oreven just as supporting material, as is common for example in medicalpractices or in hospitals. In terms of their-wide variety, hygieneproducts are now considered to be everyday products.

[0010] Hygiene paper primarily includes all kinds of dry-creped tissuepaper, as well as wet-creped paper.

[0011] The one-ply intermediate products originating from the papermachine and made of lightweight, i.e. low basis weight paper usuallydry-creped on a yankee cylinder by means of a crepe doctor are generallydescribed as “tissue paper” or more accurately raw tissue paper. Theone-ply raw tissue may be built up of one or a plurality of layersrespectively.

[0012] All one-ply or multiply final products made of raw tissue andtailored to the end user's needs, i.e. fabricated with a wide variety ofrequirements in mind, are known as “tissue products”.

[0013] Typical properties of tissue paper include the ready ability toabsorb tensile stress energy, their drapability, good textile-likeflexibility, properties which are frequently referred to as bulk(crumple) softness, a high surface softness, a high specific volume witha perceptible thickness, as high a liquid absorbency as possible and,depending on the application, a suitable wet and dry strength as well asan interesting visual appearance of the outer product surface. Theseproperties allow tissue paper to be processed into tissue products(tissue paper products) and are then available to end users in a widevariety of forms and fabrication, for example as wipes, towels,household towels, particularly as kitchen towels, sanitary products(e.g. toilet paper), paper handkerchiefs, cosmetic tissues (facials) orserviettes/napkins.

[0014] Depending on the particular application, varied and to an extentconflicting properties are frequently needed for the successful use oftissue products in their extremely broad range of applications.

[0015] For this purpose, the tissue is frequently provided withsubstances, additives, auxiliary substances and other treatmentchemicals.

[0016] In accordance with the invention, this term will also cover anysubstance or blends of substances generally referred to as treatmentchemicals and normally applied to the tissue after the drying andcreping step on the yankee cylinder.

[0017] Treatment chemicals may have an influence on physical properties,e.g. softness, particularly bulk softness, strength in the dry and wetstates, rate of absorption of liquids, particularly that of water oroil, or the structural strength of the tissue/tissue product itself,and/or they may contribute to their varying use, e.g. in the field ofskin care and protection, healthcare, etc. “Lotions” are alsoparticularly referred to in the latter case.

[0018] Household towels for example, particularly kitchen towels and toan even greater extent paper towels, require strength, especially in thewet state, and high suction capacity so as to satisfy consumer demands.In the case of toilet paper, a combination of dry strength plus goodsoftness is more likely to determine suitability in practice andacceptance among consumers. In the case of other tissue products such ashandkerchiefs or facial wipes, surface softness and excellent supplenessare predominant properties which, in addition to strength, define theserviceability of these products.

[0019] Cosmetic components contained in the product, particularly on itsouter surfaces, also play an important part in the latter tissueproducts. Such cosmetic components include, inter alia, perfumes,moisturizers, skin care agents, healthcare substances such asD-panthenol or the active camomile ingredient α-bisabolol.

[0020] It is important in the case of cosmetic components to achieve anoptimum transfer of the components such as care agents or moisturizersfrom the tissue product to the skin—optimum in the sense of an adequatequantity of such components—so as to promote the desired effect. Highamounts of the cosmetic substances to be applied to the tissue arenecessary for this purpose. On the other hand, the tissue itself mustnot feel unpleasant or e.g. leave behind a wet feeling on the skin.

[0021] Manufacturers of tissue products are therefore especially facedwith the challenge of achieving a particular balance between thevarious, frequently contradictory parameters in order to use thisbalance to obtain the optimum combinations of features required byconsumers for the desired final products. The article entitled“Weichheit und Weichmachung von Hygiene-Tissue” in the Wochenblatt furPapierfabrikation, No. 11/12, 1988, pages 435 et seq., describes indetail the properties of hygiene tissue and discusses their importanceto tissue products in different applications.

[0022] Thus, one of the principal market demands to be met bymanufacturers is a general improvement in softness across all areas oftissue products. Properties such as the softness of a tissue product aredefined in terms of their basic design by the production process,particularly by preliminary TAD and the choice of raw and auxiliarymaterials.

[0023] Softness is an important property of tissue products such ashandkerchiefs, cosmetic wipes, toilet paper, serviettes/napkins, not tomention hand or kitchen towels, and it describes a characteristictactile sensation caused by the tissue product upon contact with theskin.

[0024] Although the term “softness” is generally comprehensible, it isextremely difficult to define because there is no physical method ofdetermination and consequently no recognized industrial standard for theclassification of different degrees of softness.

[0025] To be able to detect softness at least semi-quantitatively,softness is determined in practice by means of a subjective method. Todo so, use is made of a “panel test” in which several trained testpersons give a comparative opinion.

[0026] In simplified terms, softness can be subdivided into its maincharacteristics, surface softness and bulk softness.

[0027] Surface softness describes the feeling perceived when e.g. one'sfingertips move lightly over the surface of the sheet of tissue. Bulksoftness is defined as the sensory impression of the resistance tomechanical deformation that is produced by a tissue or tissue productmanually deformed by crumpling or folding and/or by compression duringthe process of deformation.

[0028] The application of the aforementioned treatment chemicals withwhich e.g. the desired softness characteristics or other properties areto be achieved is brought about in the prior art by different roll andspray application techniques. Other methods include impregnationtechniques.

[0029] WO 94/05857 describes a method of applying a chemicalpaper-making additive to a dry tissue paper mat (tissue paper nonwovenfabric, raw tissue). The application technique is characterized by thefollowing steps: provision of a dry tissue paper mat, dilution of achemical paper-making additive using a suitable solvent to form adiluted chemical solution, the application of this diluted chemicalsolution to a heated transfer surface, partial evaporation of thesolvent through the transfer surface to form a film that contains thispaper-making additive and the transfer of this film from the heatedtransfer surface to the surface of the tissue mat.

[0030] EP-A-03 47 177 relates to a method of making soft tissue papercomprising the following steps: forming sheets from an aqueoussuspension of cellulose fibers to form a mat, application of asufficient amount of water-soluble non-cationic surfactant and dryingand creping the mat, this tissue paper exhibiting a basis weight of 10to 65 g/m² and a density of less than 0.6 g/m³.

[0031] The treatment solution can therefore be added both in the wetsection of a tissue paper machine (wadding machine), at the end of thescreen section, before or inside the press section (mechanicaldrainage), i.e. in the case of solid contents between 20 and 50%, and inthe dry section disposed after the press section in the case of solidcontents of 40 to 97% fibrous dry weight.

[0032] The prior art is represented by feed sites on the transferscreen/belt, e.g. ahead of mat transfer in a TAD layout, and the supplyto the moist fibrous mat after its transfer to the transport (dry) feltbefore the press or presses in a conventional single-felt or double-felttissue machine.

[0033] The supply of treatment chemicals by spray application onto theyankee cylinder is also known in the prior art.

[0034] The addition of the treatment agent within the tissue makingmachine is brought about by spray application onto the pope roller toproduce a film of treatment agent and subsequently to transfer it to thetissue web during rolling up. The already creped “tissue web” usuallystill exhibits a residual temperature of between 20° C. and about 70° C.as a result of the preceding drying process on the yankee cylinder,which benefits the distribution of treatment agent and its penetrationof the raw tissue.

[0035] In addition to spray application via a nozzle bar, the use ofcentrifugal rotors or brush units is possible. Application may also beeffected directly onto the tissue paper web.

[0036] Addition of the treatment agent, within a so-called doublingmachine or within the processing machine, to the outer plies of themultiply doubled web before or during calibration/smoothing is generallypreferred.

[0037] Application of the treatment agent to the outer plies of the webfrequently takes place within the processing machine, the web beingguided in multiply fashion by use of a plurality of unwindings in theprocessing machine or being previously doubled in multiply fashion.

[0038] WO 98/41687 describes a method of making tissue products of theaforementioned kind, this method being characterized by the fact that acomposition of the above type is applied to the fibrous mat or tissueweb within the screen section, press section, TAD section, on the yankeecylinder and/or dry section, i.e. at a fibrous material density of 20 to97%, relative to the web's dry fibrous weight, in an amount of 0.1 to40%, preferably 1 to 20%, continuously or discontinuously on or withinthe web and the web may undergo post-smoothing after application.

[0039] An alternative embodiment mentioned in this document relates to amethod of making tissue products, this method being characterized by thefact that a composition of the above type is applied to the fibrous mator tissue web after the dry section on the wadding machine, doublingmachine and/or in the automatic processor in an amount of 0.1 to 40 wt.%, preferably 1 to 20 wt. %, continuously or discontinuously on orwithin the web and the web may undergo post-smoothing after application.

[0040] The techniques described above teach either application methodsin which the treatment chemicals are to penetrate the tissue as evenlyas possible, or relate to the external application of treatmentchemicals in a single layer that does not completely penetrate thetissue.

[0041] If the treatment compositions are blends of several componentsapplied in a single layer, individual components sometimes cannotdevelop their action to an optimum degree. An example of this isrepresented by cosmetic lotions that protect the skin upon contact withthe tissue, in combination with (poly)siloxanes that influence thetissue's surface softness.

[0042] Another disadvantage entailed by the application of blends isthat the individual constituents of the treatment composition oftenexhibit very different physical properties so that the application maycause technical difficulties in a single application process.

OBJECT OF THE INVENTION

[0043] It is therefore the present invention's object to make availablea method that enables a controlled distribution of treatmentcompositions (e.g. lotions) in a fiber-based planar product,particularly tissue, the distribution being optimized for eachparticular use.

[0044] It is also the present invention's object to provide a planarproduct, particularly tissue, that is characterized by a correspondinglyoptimized combination of features.

DESCRIPTION OF THE INVENTION

[0045] These objects are solved by a method of applying treatmentchemicals to a dry fiber-based planar product, particularly dry, crepedtissue, such a method comprising the steps of:

[0046] a) applying a first treatment composition containing at least afirst treatment chemical to a planar product so as to produce a firstlayer having at least a first treatment chemical, and

[0047] b) applying at least a further treatment composition containingat least one other treatment chemical to produce another layer on thefirst layer, this further layer having at least one other treatmentchemical.

[0048] One advantage of this dry web method, when compared to wet webmethods, is the unrestricted use of chemicals, regardless of their heatsensitivity, since the chemicals added are not subjected to heating inthe drying section of a tissue paper machine (after the wet-laying of afibrous web). Further the method of the invention allows (more or less)saturating the tissue web with the first layer which can enhance thelocalization of the “further layer(s)” of treatment chemicals on thesurface of the tissue material. This localization is more difficult toachieve with wet web methods. Moreover it is believed that somechemicals adhere better to dried cellulosic fibres than to wet ones.

[0049] The above steps (a) and/or (b) may optionally be followed bydrying steps to remove any volatile constituents such as solvents.

[0050] Upon application of more than two layers, the “other” treatmentchemicals differ from the treatment chemical of that layer to which theyare applied. The application of two layers is preferred.

[0051] The term “layer” as used here in conjunction with the applicationof treatment compositions is not restricted to layers located on theouter surface of the fiber-based planar product, particularly tissue.The first (inner) layer in particular can thus completely penetrate theplanar product, especially tissue. These layers may also partially, butnot fully overlap.

[0052] The first layer and further layer(s) can be applied in successionusing the same device, though in different conditions, particularly atdifferent temperatures. For example, if the intention is to apply asolid (at room temperature, e.g. a wax) and a liquid, it is possible towork e.g. in succession using two pressure rolls of the same type, theroll that applies the solid being heated. Such a systematic applicationplays a major role particularly in the cosmetic lotions sector wheremany constituents exhibit softening temperatures above 25° C., but donot need any excessive heating (e.g. no more than 80° C.) to beconverted into the liquid state.

[0053] Alternatively, the first layer and further layer(s) can besuccessively applied using different devices.

[0054] Depending on the properties of the treatment composition to beapplied, the application device(s) are for example chosen from among aspray unit (e.g. via a nozzle bar), a cooling tower, a brush unit, acentrifugal rotor, a calender and/or an application roll (e.g. pressurerolls). A transfer technique can also be adopted, as described e.g. inWO 94/05857.

[0055] A suitable time for application of the first and/or other layerswithin the production of the planar product, e.g. tissue (paper)manufacturing, can be chosen in a manner known to specialists. Theapproaches described in the introductory section of the application inrelation to the prior art are, for instance, also suitable here. In thecase of a conventional single-felt or double-felt tissue machine, thetreatment composition can be applied e.g. by feeding it to the moistfiber mat after its transfer to the transport (dry) felt. In the case ofapplication as a pure substance, particularly when the treatmentcompositions exhibit a high viscosity, pressure rolls or calenders areparticularly suitable.

[0056] The treatment composition may comprise a single treatmentchemical or a blend of at least two treatment chemicals. This treatmentcomposition may also contain compounds that have no influence or only aslight influence on the properties of the treated planar product,particularly tissue, e.g. solvents (such as water and/or alcohol),auxiliary substances and/or additives. It may therefore be present e.g.as an aqueous solution or dispersion (e.g. suspension or emulsion) orcomprise one or more treatment chemicals (water not included). Watermay, however, also be an important active constituent of the treatmentcomposition, particularly in cosmetic lotions intended to achieve apleasant moist sensation on the skin. Water is then preferably used incombination with hygroscopic compounds such as the polyhydroxy compoundsdescribed below. Depending on the treatment composition's function, theproportion of optionally present solvents (including water) in thecomposition is preferably less than 60 wt. %, with greater preference onless than 30 wt. %, even greater preference on less than 10 wt. %,particularly less than 5 wt. %, each relative to the total weight of thecomposition.

[0057] The treatment chemical(s) may be selected from the followingcompound classes or compounds.

[0058] Agents for skin care and protection, so-called cosmetic lotionssuch as

[0059] moisturizers, such as substituents for the skin's naturalmoisturizing factor (NMF) that contain e.g. cleavage products ofcollagen, glycerol etc.;

[0060] skin care agents, e.g. long-chain fatty acid esters (likesorbitan fatty acid ester or Cetiol®), lanolin or derivatives thereof;

[0061] fragrances, e.g. natural, naturally identical or artificialperfumes; and/or

[0062] active cosmetic ingredients like D-panthenol or the activecamomile ingredient α-bisabolol or agents exhibiting other functions,e.g.

[0063] strength-enhancing agents, particularly wet-strength agents likeepichlorohydrin resins or crosslinked polyalkylene amines,

[0064] agents that promote the softness (e.g. bulk softness or surfacesoftness) of the planar product, particularly the tissue; e.g. apolyhydroxy compound (e.g. ethylene glycol, propylene glycol, a liquidpolyethylene glycol (derivative), a liquid polypropylene glycol(derivative) and/or glycerol), also quaternary ammonium compounds asdescribed e.g. in U.S. Pat. No. 5,312,522 or 5,397,435 and the prior artcited therein, optionally in combination with the polyhydroxy compoundsdescribed in both these documents; or a poly(siloxane), particularly the(poly)siloxanes described in EP-A-347 153 and EP-A-347 154,

[0065] surfactants used e.g. as absorption rate control agents, e.g.long-chain quaternary ammonium compounds that may also exhibitsoftness-promoting action,

[0066] waxes, oils, and/or

[0067] inorganic or organic pigments or dyes.

[0068] A preferred basic composition for improving softness, especiallybulk softness, comprises the following recipe:

[0069] glycerol: 40-45%

[0070] propylene glycol: 28-30%

[0071] linden extract: 2.5-3.5%

[0072] water up to 100%

[0073] The total amount of nonvolatile treatment chemical(s) applied inthe treated surface area of the planar product, particularly tissue, ispreferably 0.01 to 50 wt. %, with greater preference on 0.5-45 wt. % andeven greater preference on 0.75-40 wt. %, relative to the weight of theuntreated oven-dried planar product, particularly tissue (oven-driedbeing understood in accordance with German standard DIN EN 20638). Evengreater preference is given to values of 1-35 wt. %, particularly 2-30wt. % (what is considered to be volatile is any component thatvolatilizes upon further processing of the planar product, especiallytissue, e.g. solvent such as water, unless it is intended to remain inthe composition, e.g. a cosmetic lotion.).

[0074] The first layer preferably comprises a (poly)siloxane and/or asurfactant. Surfactants may exhibit an action that acceleratesabsorption (as regards any liquids applied to the planar product) and/orpromote the softness of the planar product, particularly tissue.(Poly)siloxanes, e.g. the compounds described in EP-A-347 153 andEP-A-347 154, promote the tactile properties, especially softness, ofthe planar product, particularly tissue.

[0075] The other layer (particularly the outer-most layer) preferablycomprises one or more constituents of a cosmetic lotion. In this way,the cosmetic constituents can completely develop their effect during use(e.g. skin care, surface softness etc.) without any interference fromthe treatment chemical(s) of the first layer. The cosmetic lotion ispreferably creamy.

[0076] In a preferred embodiment, the first layer contains a(poly)siloxane and/or a surfactant in a total amount of 1-3 wt. %, andthe second layer contains one or more constituents of a cosmetic lotionin a total amount of 4-5 wt. %, each relative to the planar product(oven-dried).

[0077] In a further preferred embodiment

[0078] the first layer contains at least one treatment chemicalimparting bulk softness to the fibrous planar material, in particulardry, creped tissue material, e.g. a polyhydroxy compound (for instancein the form of the above-explained basic composition) or a quaternaryammonium compound as described above, and

[0079] the second layer contains at least one other treatment chemical,preferably agents classified as cosmetic lotions and/or treatmentchemicals imparting surface softness to the fibrous planar material, inparticular dry, creped tissue material, e.g. poly(siloxanes) asmentioned.

[0080] The present invention also relates to a fiber-based planarproduct, in particular a dry, creped tissue material, that contains atreatment composition; this product can be obtained according to amethod that comprises the steps described above. The term “fiber-basedplanar product”, as used here, stands for planar products made of fibers(especially fibers that contain cellulose, such as pulp), for examplenonwovens or tissues, with tissue representing a particularly preferredembodiment.

[0081] The term “tissue” as defined by the present invention isunderstood as any kind of creped paper made from an aqueous dispersionand having a basis weight range of usually between 10 and 65 g/m². Inaccordance with the invention, the term “tissue” covers both

[0082] the entire range of raw creped paper, also known as “raw tissue”,particularly the range of dry-creped raw tissue paper, regardless ofwhether they are single-layer or multilayer,

[0083] and any single-layer or multilayer end products made of thiscreped raw paper.

[0084] “Raw tissue” is usually made as a one-ply tissue web in thetissue (paper) machine or as an optionally multiply (intermediate)product, e.g. in the form of multiply doubled webs or in the form ofmaster rolls for further processing. The term “layers” refers to achange in chemical and/or physical properties within a tissue ply; sucha change may be caused e.g. by a different fiber composition. Incontrast to plies, layers usually cannot be separated from one another.

[0085] The final product is preferably

[0086] a cleaning wipe, e.g. wiping paper, a windscreen cleaning wipe, acleaning wipefor industrial applications, a towel or a cleaning wipeforhousehold use, e.g. kitchen paper;

[0087] a sanitary product, e.g. toilet paper (also moist);

[0088] a paper handkerchief (also moist);

[0089] a household towel, e.g. kitchen towels;

[0090] a towel;

[0091] a tissue for facial use, e.g. a makeup removal tissue (facial) orcosmetic tissue,

[0092] a serviette/napkin,

[0093] bed linen;

[0094] a garment, e.g. disposable apparel for hospitals or kitchenstaff.

[0095] Particularly preferred tissue products are handkerchiefs, tissuesfor facial use, sanitary products (e.g. toilet paper) and towels inwhich the application of cosmetic treatment compositions and/ortreatment compositions that convey softness (lotions) plays a part.

[0096] The term tissue paper must also be regarded independently of thefibrous raw material to be used, particularly irrespective of whetherthe fibrous raw material is made solely or mainly from natural pulpse.g. according to the sulfate or sulfite process, or is used in amixture with chemothermomechanical wood pulps (e.g. CTMP, or HTCMP), orwhether the fibrous raw material used comes from a secondary fiberrefinement process and whether the fibrous raw material needed to maketissue therefore completely or partially comprises “recycled fibers”.

[0097] To distinguish from nonwovens, it should be noted that althoughthe predominant use of natural (cellulose-containing), i.e. vegetable,pulp fibers broken up in a manner suitable for paper making is typicalof tissue paper manufacturing, a proportional use by refinement ofmodified pulp fibers in a range of 10 to 50 wt. %, relative to the totalweight of the fibers, or even a use of synthetic fibers suitable forpaper making in an amount of 10 to 30% are covered by the aforementioneddefinition of the term “tissue”. It is analogously possible to apply themethod beyond the field of paper making to corresponding fields in thenonwoven and textile sectors.

[0098] Upon application of the treatment composition, it is possible tostart out e.g. from a multiply, usually two-ply to four-ply or multiply(doubled) master roll produced in a separate doubling machine. Aplurality of one-ply tissue webs can alternatively be treated (oneunwinding each) and then jointly rolled up into a multiply tissueproduct via a roll-up device. This produces the advantage that e.g. theinner plies can be treated with a treatment chemical other than that forthe outer plies. For example, the inner plies of a four-ply end productcan remain untreated, or can be treated with a strength-enhancing agent,whereas the two outer plies were treated with a treatment chemical toimprove surface softness. In principle, an extremely wide variety ofcombinations of differently treated tissue plies is conceivable.

[0099] In one embodiment, the tissue is a four-ply or three-ply doubledraw tissue for making handkerchiefs or facials, the tissue being madeavailable in the form of master rolls for the application of a treatmentagent in a processing machine suitable for this purpose. The processingmachine comprises at least one unwinding device for the master rolls, aroll-up device for the product finished after application of a treatmentagent, and an interposed applicator for applying the treatment agent.

[0100] To explain the present invention, reference is also made to theintroductory portion of the specification where general properties andproduction steps are described in more detail for tissue (products).

1. A method of applying treatment chemicals to a dry, creped tissuematerial, said method comprising the steps of: a) applying a firsttreatment composition containing at least one treatment chemical to saiddry, creped tissue material to produce a first layer having at least onefirst treatment chemical, and b) applying at least one further treatmentcomposition containing at least one other treatment chemical to produceat least one further layer on said first layer, said further layerhaving at least one other treatment chemical.
 2. A method according toclaim 1, wherein said first layer and further layer(s) are applied insuccession using the same device, though under different conditions. 3.A method according to claim 2, wherein said layer(s) is (are) applied atdifferent temperatures.
 4. A method according to claim 1, wherein saidfirst layer and further layer(s) are applied in succession usingdifferent devices.
 5. A method according to claim 1, wherein two layersare applied.
 6. A method according to claim 1, wherein said first andother layer(s) are applied by at least one application means selectedfrom spray units, dripping or trickling installations, brush units,centrifugal rotors, calenders and application rolls.
 7. A methodaccording to claim 1, wherein said treatment compositions appliedcontain at least one constituent selected from moisturizers, skin careagents, fragrances, active cosmetic ingredients, strength-enhancingagents, agents that promote the softness of the tissue material,surfactants, waxes, oils, inorganic or organic pigments and dyes.
 8. Amethod according to claim 1, wherein said treatment chemicals areapplied in total amounts of 0.01 to 50 wt. %, relative to the tissuematerial (oven-dried).
 9. A method according to claim 1, wherein saidfirst layer contains at least one treatment chemical selected from(poly)siloxanes and surfactants.
 10. A method according to claim 1,wherein said further layer contains one or more constituents of acosmetic lotion.
 11. A method of applying treatment chemicals to a dry,creped tissue material, said method comprising the steps of: a) applyinga first treatment composition containing at least one treatment chemicalselected from (poly)siloxanes and surfactants to said dry, creped tissuematerial to produce a first layer, and b) applying at least one furthertreatment composition containing at least one other treatment chemicalselected from constituents of a cosmetic lotion to produce at least onefurther layer on said first layer.
 12. A method according to claim 11,wherein said first layer contains a (poly)siloxane and/or a surfactantin a total amount of 1-3 wt. %, and said further layer contains one ormore constituents of a cosmetic lotion in a total amount of 4-5 wt. %,each relative to the tissue material (oven-dried).
 13. A tissue materialobtainable by a method of applying treatment chemicals to a dry, crepedtissue material, said method comprising the steps of: a) applying afirst treatment composition containing at least one treatment chemicalto said dry, creped tissue material to produce a first layer having atleast one first treatment chemical, and b) applying at least one furthertreatment composition containing at least one other treatment chemicalto produce at least one further layer on said first layer, said furtherlayer having at least one other treatment chemical.
 14. A tissuematerial according to claim 13 having two layers.
 15. A tissue materialaccording to claim 13, wherein said treatment compositions appliedcontain at least one constituent selected from moisturizers, skin careagents, fragrances, active cosmetic ingredients, strength-enhancingagents, agents that promote the softness of the tissue product,surfactants, waxes, oils, inorganic or organic pigments and dyes.
 16. Atissue material according to claim 13, wherein the total amount oftreatment chemicals is 0.01 to 50 wt. %, relative to the tissue material(oven-dried).
 17. A tissue material according to claim 13, wherein thefirst layer contains at least one treatment chemical selected from(poly)siloxanes and surfactants.
 18. A tissue material according toclaim 13, wherein the further layer contains one or more constituents ofa cosmetic lotion.
 19. A tissue material obtainable by a method ofapplying treatment chemicals to a dry, creped tissue material, saidmethod comprising the steps of: a) applying a first treatmentcomposition containing at least one treatment chemical selected from(poly)siloxanes and surfactants to said dry, creped tissue material toproduce a first layer, and b) applying at least one further treatmentcomposition containing at least one other treatment chemical selectedfrom constituents of a cosmetic lotion to produce at least one otherlayer on said first layer.
 20. A tissue material according to claim 19,wherein said first layer contains a (poly)siloxane and/or a surfactantin a total amount of 1-3 wt. %, and said further layer contains one ormore constituents of a cosmetic lotion in a total amount of 4-5 wt. %,each relative to the tissue material (oven-dried).